Glyphosate-Resistant Canada Fleabane Control in Winter Wheat with Postemergence Herbicides

Table 1

Glyphosate-resistant Canada fleabane (GRCF) control 2, 4, and 8 weeks after herbicide application (WAA), GRCF density, and dry biomass 4 WAA and winter wheat yield for herbicides applied postemergence from 6 sites in southwestern Ontario in 2018–2019.

Herbicide treatment	Rate (g ai ha^−1)	GRCF Control (%)			GRCF density (plants m^−2)	GRCF dry biomass (g m^−2)	Winter wheat yield (T ha^−1)
		2 WAA	4 WAA	8 WAA
Weed-free control		100	100	100	0 a	0 a	4.13 ab
Weedy control		0 f	0 e	0 e	142.1 h	10.8 e	3.58 b
Pyrasulfotole/bromoxynil + AMSa (1 L ha^−1)	205	89 ab	97 ab	98 ab	0.7 abc	0.25 abc	4.31 ab
2,4-D ester	850	76 abc	93 ab	94 ab	6.4 bcde	0.37 abc	4.09 ab
Thifensulfuron-ethyl/tribenuron-methyl + fluroxypyr + MCPA ester + NISb (0.2% v/v)	15 + 70 + 280	62 bcd	74 bc	71 bc	17.1 def	1.46 bc	3.96 ab
Halauxifen-methyl + MSOc (1% v/v)	5	76 abc	98 ab	99 ab	0.8 abc	0.08 ab	4.36 ab
Fluroxypyr/halauxifen-methyl + MCPA EHE	82 + 372	78 abc	97 ab	98 ab	1.9 abcd	0.20 abc	4.19 ab
Pyroxsulam + NIS (0.25% v/v) + UANd (2 L ha^−1)	15	19 e	8 d	7 d	49.9 fg	8.58 de	3.96 ab
Pyrasulfotole/bromoxynil/fluroxypyr	277	91 ab	98 ab	98 ab	2.3 abcd	0.20 abc	4.16 ab
Pyrasulfotole/bromoxynil/thiencarbazone-methyl +  AMS (1 L ha-1)	211	94 a	100 a	100 a	0.1 ab	0.02 ab	4.56 a
Pyrasulfotole/bromoxynil/thiencarbazone-methyl +  MCPA ester + AMS (1 L ha^−1)	211 + 280	95 a	100 a	100 a	0.8 abc	0.02 ab	4.15 ab
Tribenuron-methyl + thiencarbazone-methyl +  AMS (1 L ha-1)	7.5 + 5	11 ef	5 de	4 de	55.1 gh	7.17 de	4.02 ab
Tribenuron-methyl + thiencarbazone-methyl +  MCPA ester + AMS (1 L ha^−1)	7.5 + 5 + 280	38 de	38 cd	33 cd	28.4 efg	3.12 cd	3.93 ab
Fluroxypyr/bromoxynil/MCPA	600	67 abcd	81 abc	84 ab	13.7 cdef	0.94 bc	3.67 ab
Tolpyralate + MSO (0.5% v/v) + UAN (2.5% v/v)	40	57 cd	73 bc	78 ab	6.9 bcdef	0.52 abc	4.22 ab
Fluroxypyr/halauxifen-methyl + pyroxsulam +MCPA EHE + NIS (0.25% v/v)	82 + 15 + 372	79 ab	96 ab	96 ab	1.8 abcd	0.23 abc	3.92 ab

Means within a column followed by the same lowercase letter do not differ significantly according to Tukey’s HSD at Ammonium sulfate. ^bNonionic surfactant. ^cMethylated seed oil. ^d28% urea ammonium nitrate.